Telephone systems are a ubiquitous part of modern business. Classic telephony systems worked using circuit switched networks that operated to provide routing for a telephone call between parties. Modern telephony has migrated towards packet switched networks beginning with the Signaling System 7 (SS7) networks, which use packet-based communications for signaling. The widespread acceptance of the Internet and other packet-switched networks has hastened the migration of telephony to packet switched protocols, including voice over internet protocol (VoIP) standards.
VoIP developers have tried to duplicate many of the call management services provided by SS7 networks to internet protocol (IP) networks, including, for example, call transfer. In a prior art session initiation protocol (SIP) voice communications session, call transfer involves a first party communication device instructing a second party to establish a communication connection with a third party. The first party's communication device typically has a media connection to the second party's communication device, e.g., through a media terminal adaptor (MTA) or embedded media terminal adaptor (EMTA) embedded in a cable modem.
As the first party attempts to transfer the media connection to the second party, the first party's communication device (e.g., MTA) instructs the second party's device to establish media and signaling connections with the third party's device. In some prior art implementations, the first party's device may also establish a signaling connection with the third party's device. The first party's device terminates participation in the communication session only after receiving an acknowledgement message that the transfer, or transaction, has been completed and a communication session has been established between the second and third parties. Alternatively, if the second party is unable to connect, it may signal a timeout on the connection, at which time the first party can terminate the communications session between the first party and the second party. Processing the message for the completed connection and processing for the timer can use processor resources that could be used for other processes. Similarly the network bandwidth consumed by the now unneeded connection between the first and second parties could be repurposed for other activities. Thus, there is a need in the art to terminate a transferring party's call while minimizing use of processor resources.